The commander of U.S. and NATO forces in Afghanistan says the 20-hour militant siege in Kabul was a military failure for the Taliban, but also a propaganda victory for the insurgent group.

General John Allen said Wednesday that the assault, which targeted the U.S. Embassy, NATO's headquarters and other high-profile targets in the Afghan capital, had no military significance. But he added that the raid had frightened Kabul residents and made news headlines around the world.

The siege ended Wednesday when Afghan and coalition forces killed the remaining militants who had participated in the raid.

On Tuesday, six militants on Tuesday took over a half-built high-rise building overlooking the two compounds and began firing automatic rifles and rocket-propelled grenades. Three other militants, armed with suicide vests, attacked Afghan police targets elsewhere in Kabul.

NATO helicopters working alongside Afghan security forces finally cleared the building of the last insurgents Wednesday, ending the assault.

The Taliban claimed responsibility for what is seen as the longest militant attack on the Afghan capital since the start of the war in 2001.

General Allen said 11 Afghan civilians, including children, were killed, along with five Afghan police officers. More than two dozen people were wounded, including six NATO troops.

U.S. Ambassador to Afghanistan Ryan Crocker blamed the Pakistan-based Haqqani network for the coordinated attack in the heart of Kabul. The Haqqani network has ties to both al-Qaida and the Taliban and has previously demonstrated an ability to launch sophisticated attacks.

Crocker also downplayed the assault, saying the militants were only capable of what he called “harassment,” firing six rocket-propelled grenades at the embassy from a distance of 800 meters. No embassy staff were wounded.

Afghan police officials said they believe the militants used burqas to bypass security checks to get close to the sensitive area housing the diplomatic compounds. They reported finding several of the traditional full-bodied coverings for women inside a vehicle packed with explosives at the scene of the final battle.

Afghan President Hamid Karzai condemned the attack and praised the effective response of the Afghan authorities. He said such actions will not stop the security transition in the country, but instead embolden the Afghan people's determination to take responsibility for their own country's affairs.

The assault came as NATO nations seek to transfer full security control to the Afghan military within the next few years. U.S. and NATO officials responded to the violence by saying it would not weaken their resolve to continue the transition through the end of 2014. Afghan security forces already have taken security control of several cities and provinces.